Hydrocarbon-containing materials, such as oil sands, often contain bitumen, which is an oily, highly-viscous liquid or semi-solid. Bitumen is a naturally-occurring organic byproduct of decomposed organic material. An extraction process is performed on the hydrocarbon-containing materials in order to harvest the bitumen for sale.
There are many upstream and downstream processes that involve circulating large volumes of solvent to effect a separation of a hydrocarbon-containing stream from a hydrocarbon-containing material or to clean up a hydrocarbon stream by removing high molecular weight hydrocarbons. However, such processes often consume a large amount of power. In addition, the large amount of recycle solvent that is sent through such processes adds to the already-high power demands. Oftentimes, a certain amount of power may be generated for these processes by burning some of the hydrocarbon product that is obtained. However, this method of producing power results in the loss of a certain amount of hydrocarbon product that might otherwise have been sold. Thus, research has to been performed to improve energy usage and find synergies for the generation of energy.
U.S. Pat. No. 5,843,302 to Hood discloses a solvent deasphalting apparatus capable of generating power. The solvent deasphalting apparatus includes a separator that receives two inputs, a heavy hydrocarbon feed and a solvent feed, and produces two outputs, an asphaltene/solvent stream and a deasphalted oil/solvent stream. A solvent recovery unit recovers the solvent stream, which is returned to a solvent drum. A pump is used to pump a relatively constant volume of solvent from the solvent drum into a by-pass line connecting the pump to the separator. A power generator is used to generate power in response to the flow of the solvent stream in the by-pass line. The power generator includes a vaporizer, an organic vapor turbine, a condenser, and a pump.
U.S. Pat. No. 4,760,705 to Yogev, et al., discloses a Rankine cycle power plant operating with an improved organic working fluid. The working fluid may be any of a number of different compounds, including, for example, bicyclic aromatic hydrocarbons, substituted bicyclic aromatic hydrocarbons, or heterobicyclic aromatic hydrocarbons. Such compounds are inherently stable in the temperature range of interest for the Rankine cycle power plant. More specifically, the molecular weight of such compounds is less than the molecular weight of many conventional working fluids and, thus, results in a lower Mach number at the turbine exit, thereby increasing the efficiency of the turbine.
International Patent Publication No. WO2007/104970 by Smith discloses a method for working fluid control in non-aqueous vapor power systems. Power is generated from heat from a source, and the heat is used to boil a non-aqueous working fluid by heat exchange in a boiler. Wet vapor from the boiler is fed by a line to a positive displacement twin-screw expander. The expanded fluid is fed by a line to a condenser and then returned to the boiler by a feed pump. The flow rate through the boiler and the expander is controlled by a controller responsive to pressure and temperature sensors monitoring a flow through a chamber to control the dryness of the fluid in the line, and lubricant for the expander may be included in the liquid phase.